70 research outputs found
Left Ventricular Chamber Quantification With Three-Dimensional Echocardiography:A Clinical Perspective
Integrating Building Information Management (BIM) in Civil Infrastructure Coordination: Application at LUSAIL Plaza
The purpose of this case study is to highlight how the BIM modelling can lead to a
smooth construction process for MEP (Mechanical, Electrical & Plumbing), Civil,
Architectural, and Landscape works, which can aid the engineers in various project
phases. An exploratory approach on a complex mega-project case study (El-Sadek &
McCabe, 2017), where the project team was coached on exploring the BIM model to
identify any clash and discuss with the technical team to come up with adequate solutions,
which was done by holding twice a week regular meetings. This paper introduces the
issues appeared during the early phases of the design process and continued all the
way through the construction phases. While preparing the composite shop drawings,
where each discipline/installation will have a clear corridor without interference with
other disciplines/installations, and in a manner sufficient to ensure the avoidance of
any clash that may arise during construction. However, what happens if the available
corridor for all disciplines is very congested and insufficient to enable the designers from
accommodating the space needed into coordination process? This case study triggers
the need for identifying a new process in integrating BIM models in the coordination
challenges through all the phases of mega-projects, as the complexity associated with
mega projects appears to increase from one phase to another. From the lesson learned
in this case study readers will know how integrating BIM in the coordination process in
complex scale projects can decrease the clashes and improve progress of work during
construction phase
Downhole Wireline Mechatronics and Drillstring Vibration Dynamics
The work is divided into two parts: The First part discusses and documents simulation investigations on the interactive effect of the different conveyance accessories tools and their designs on the wireline cable tension force, and how it can influence the wireline cable performance especially in open hole logging operations with highly deviated and rugose zones. A computer simulation model was built to predict the cable tension force applied on conveyed wireline string so as to assess and analyze the effect of the different conveyance accessories, such as centralizers, bottom-nose tools, and wireline coating, on wireline penetration rates. A numerical computing approach was then utilized to represent and analyze the simulation studies output results in a friendly graphical form. Improving the wireline logging performance, especially in highly deviated rugose openhole wells, could increase the percentage of successful logging operations, reducing time, cost and improving data quality with the increased wellbore coverage. The second part discusses the possible violent drillstring vibrations encountered during drilling and its effect on the overall rate of penetration and sustainability. This entails a complete identification and modeling of the drillstring dynamics and the sources of vibrations excitation that include stick-slip, bit-bounce, and whirling with its two forward and backward types to better control its functional operation and improve its performance.
A Matlab numerical simulator model based on Finite-Element-Method of 3D- Timoshenko beam elements is developed for this purpose to predict and simulate the rotordynamic behavior of the bottom-hole-assembly (BHA) and the PDC-Drillbit cutting dynamics. The model also includes the coupling between the torsional and bending vibrations of drillstrings with the nonlinear effects of drillstring/wellbore friction contacts. The work extends previous models of drillstring vibrations in the literature to include the destructive drillstring vibration backward whirling type with Pure rolling behavior and answers some crucial questions: the operation conditions that possibly causes backward whirl vibrations, possible stabilizers’ configuration to reduce chance of backward whirl, best stabilizers locations in the BHA to minimize the sever vibration effects on the drillstring, and other arising questions
Biochemical profile, antioxidant effect and antifungal activity of Saudi Ziziphus spina-christi L. for vaginal lotion formulation
Ziziphus spina-christi L. extract from the northern region of Saudi Arabia, was investigated to determine its chemical composition and to evaluate its antioxidant and antifungal properties. Fresh leaves were extracted using Soxhlet apparatus and the yield was 8% w/w. Results of the qualitative study showed that this extract is rich in chemical compounds belonging to several classes (saponins, phenols, tannins). GC-MS analysis detected 38 chemical compounds with different concentrations representing 99.71 % of the total extract. However, Z. spina-christi leaves extract is mainly composed of Octadecanoic acid, 2-hydroxy-1-(hydroxymethyl)ethylester (18.80%). The extract has free radical scavenging activity at different concentrations and the best result was obtained with IC50 of 148.33 µg/ml. C. albicans and other Candida species caused vulvovaginal candidiasis, which is a high-risk occurrence in hospitalized patients. In vitro antifungal activity was investigated by the agar well diffusion test to measure and compare diameter of zones of inhibition (in mm) against Candida albicans, Candida glabrata and Candida tropicalis. Ethanolic extract of Z. spina-christi demonstrated a substantial inhibitory impact on several Candida species, especially against C. glabrata which has the highest inhibitory effect (90%). Therefore, Saudi Z. spina-christi leaves extract is a source of natural antioxidants and it can be used as well antifungal pharmaceutical product
Challenges to Safe Wheat Storage
There are enormous challenges facing wheat storage, which is the most important crop in existence. Wheat is one of the most famous and important plants in human history. There is no country in the world that does not give up wheat yields. Countries of the world vary and differ in their production and consumption of that important plant. Since ancient times, humans have stored wheat grain in special places. Storage areas were developed until the current silos were reached. With large quantities of wheat stored in silos, there are many challenges to the healthy environment of storage. One of the most important challenges facing quality of wheat stored in silos is the spread of conidia and spores of many dangerous fungi on wheat grains. One of studies conducted by the authors proved presence of some of notorious fungi on and inside wheat mass stored in the silo under study. Aspergillus flavus, A. niger, Circinella umbellata, Gliocladium sp., Penicillium frequentans, P. islandicum, and Ulocladium atrum were isolated from wheat samples. All seven isolated fungi demonstrated their ability to analyze human red blood cells with different strengths. These results are consistent with previous studies that confirm the seriousness of presence of these fungi on the health of dealers and exposers especially with bad storage and humidity
Olive-Pressed Solid Residues as a Medium for Growing Mushrooms and Increasing Soil Fertility
Organic fertilizer is the core of organic farming, which represents the most important way to provide crops and agricultural products that are safe and free of any chemical components and pesticides. From this point of view, the purpose of this study is to provide a source of organic fertilizers which was formerly an environmental problem. The northwestern region of Saudi Arabia is flourishing with olive production, leaving huge amounts of residues called olive press cake (OPC). These wastes are a major environmental pollution despite their good content of carbohydrates, protein, oil and cellulose alongside phenols and lignin. We tested the cultivation of Gliocladium roseum, Pythium oligandrum and Trichoderma harzianum and the mushroom Pleurotus ostreatus on OPC in order to reduce the high percentage of phenols that impede the germination of some plant seeds. Gliocladium roseum, Pythium oligandrum and Pleurotus ostreatus were able to reduce the percentage of phenols to more than 40% and thus support germination of seeds of Eruca sativa. This study gave than one benefit: firstly, reducing phenols that impede the germination of seeds. Secondly, Gliocladium roseum and Pythium oligandrum work against some plant diseases and also produce plant-like hormones that increase growth of plants
Late life vascular risk factors and their association with dementia and Alzheimer’s disease
Background : Epidemiological studies have demonstrated associations between higher levels of vascular risk factors in midlife and later development of dementia, particularly Alzheimer's disease (AD). However, in elderly subjects with dementia, some studies have shown that these associations may decrease or even reverse. Therefore , our study aimed to find the association between late life cardiovascular risk factors and neurodegenerative dementia in general and AD in particular. Methods :It is a retrospective case control study using electronic medical records that included elderly patients that were reviewed in Ahmadi hospital geriatric clinic , Kuwait , from the period of 1/7/2019 to 1/2/2020. Two hundred and three (203) elderly patients with neurodegenerative dementia (study group) were recruited for this retrospective study and compared to two hundred and one (201) controls with normal cognition for the presence of vascular risk factors.Results :The study included 404 subjects .Age ranged from 60 to 107 years (mean age 78.79, ± 8.13 SD). AD was found to be the most prevalent type of dementia in the study group , as 49.3 % (100/203) of the demented patients were diagnosed with AD. No significant statistical association was found between vascular risk factors and dementia (P>0.05) , except for obesity which showed negative association (P<0.001). Regarding AD , no statistical significance was found between AD and diabetes, hyperlipidemia, smoking nor atrial fibrillation. On the other hand, we found obesity and hypertension more prevalent in the normal cognition group (negative association with P value <0.001,0.05 respectively). Conclusion : The results of our study support an emerging concept that, while elevated levels of vascular risk factors in midlife increase the risk of development of dementia and AD later in life, once dementia begins , these associations may be diminished or reversed in the elderly
Численный анализ естественной конвекции кориума в полуцилиндрической полости с изотермическими стенками
В настоящей работе проводится моделирование естественной конвекции кориума в полуцилиндрической полости с изотермическими стенками в ламинарном приближении. Для описания влияния выталкивающей силы внутри тепловыделяющей среды используется модель Буссинеска. Для реализации задачи, сформулированной на основе преобразованных переменных, применяется метод конечных разностей. Полученные результаты отражают влияние определяющих параметров на структуру течения и теплоперенос, а также на эволюцию интегральных характеристик
Fruiting of the Barhy Date Palm (Phoenix Dactylifera L.) Through New Pollination Technique Under Conditions in El-Dakhla, New Valley, Egypt
Pollination is a critical process in date palm production lines that affects yield and fruit quality. The main aim of this study was to evaluate the effect of different pollination methods (dusting of pollination powder and spraying of pollen grain suspension with sugar or ascorbic acid) on yield and fruit quality of Barhy date palm. This study was conducted in El-Dakhala Oasis, New Valley during the 2019, 2020 and 2021 growing seasons. After three and six days of pollination, the modified approach (trimming 25% of tufts and setting 10 tufts/spathe plus dusting with 0.1 g pollen powder and bagging with shaking) or spraying female spathes with 1 g pollen grains + 10% ascorbic acid produced a higher performance yield and improved fruit quality. Furthermore, the proposed modified method of combining pollination and thinning has various advantages; including saving time, effort, labor and cost, and improving applicability, and can be recommended as a promising pollination strategy for the future
Improving Pollination Efficiencies of Certain Arab Date Palm Cultivars Grown under New Valley Conditions
Pollination is a critical process in date palm production lines that affects yield and fruit quality. This study aimed to evaluate the effect of sprayed pollen grain powder on yield and fruit quality of Madjool, Segae and Khodry date cultivars. This study was conducted in Dakhla Oasis, New Valley Governorate, Egypt during the 2019 and 2020 seasons. Results showed that the most beneficial treatment in this concern is spraying female spathes with 0.5 to 1 g pollen grains plus 10% sugar/L water which gave economical yield with good fruit quality. Moreover, it is distinguished to increase the pollination efficiency and save time, effort, labour and cost likewise more practical because it plays a promising in pollination technique in the future
- …